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问题 单项选择题

以完整、色棕黄、质松脆、断面层纹清晰而细腻者为佳的药材是

A．羚羊角

B．麝香

C．牛黄

D．珍珠

E．蕲蛇

答案

参考答案：C

解析：牛黄以完整、色棕黄、质松脆、断面层纹清晰而细腻者为佳。故答案选C。

单项选择题

There has been much speculation about the origin of baseball. In 1907 a special commission decided that the modern game was invented by Abner Doubleday in 1839. One hundred years later the National Baseball Museum was opened to honor Doubleday. Historians, however, disagree about the origin of baseball. Some say that baseball comes from bat-and-ball games of ancient times. It is a matter of record that in the 1700s English boys played a game they called "baseball". Americans have played a kind of baseball since about 1800. At first the American game had different rules and different names in various parts of the country — "town ball", "rounders", or "one old cat". Youngsters today still play some of these simplified forms of the game.Baseball did not receive a standard set of rules until 1845, when Alexander Cartwright organized the Knickerbocker Baseball Club of New York City. The rules Cartwright set up for his nine-player team were widely adopted by other clubs and formed the basis of modern baseball. The game was played on a "diamond" infield with the bases 90 feet apart. The first team to score 21 runs was declared the winner. By 1858 the National Association of Baseball Players was formed with 25 amateur teams. The Cincinnati Red Stockings began to pay players in 1869.

The tone of the passage is________.

A．persuasive

B．informative

C．biased

D．argumentative
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选择题

质量为1kg的物体静止在光滑水平面上，某时刻受到水平拉力F的作用（F－t图像如图所示），若在第1 s内物体受到的拉力F向右，关于物体在0～3 s时间内的运动情况，下列说法正确的是

A．0～3 s时间内物体先向右运动，再向左运动

B．0～3 s时间内物体始终向右运动

C．物体在第1 s末的速度最大

D．物体在第3 s末的速度最大
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